Continue follow-up on the total population of study and control women for ascertainment of breast cancer incidence and deaths in a minimum period exposure of fifteen years following entry into the study; continue the intensive follow-up of all study and control group women with diagnosed breast cancer for ascertainment of survival status or cause of death; continue data collection on breast cancer incidence cases and general mortality; continue and extend data analysis. Reexamination of breast cancer risk factors and analysis of costs in conducting the study has been eliminated from the workscope.